Why this bond is forfeit,
And lawfully by this the Jew may claim
A pound of flesh, to be by him cut off
Nearest the merchant's heart.
         —The Merchant of Venice, 4.1.227-30

When Paul declares that "the circumcision is of the heart" and is "in the spirit, not in the letter," we are presented with a double displacement: of the physical by the spiritual and of the circumcision of the flesh by the circumcision of the heart. Elizabethan commentators were well aware that Paul's metaphorical treatment of circumcision builds upon a preexisting tradition in the Old Testament, expressed particularly in Deuteronomy 10.16 and 30.6: "Circumcise the foreskin of your heart," and "The Lord thy God will circumcise thine heart."⁶¹ Mornay, in Sidney's translation, also notes that when the Old Testament prophets "rebuke us, they call us not simply uncircumcised, but uncircumcised of heart or lips,"⁶² and Peter Martyr simply confirms that "Paul borrowed" this "phrase touching the circumcision of the heart … out of the Old Testament."⁶³

Hugo Grotius understood that this substitution of heart for flesh neatly defined the relationship between Christian fellowship and the genealogical Judaism it replaced, since the Covenant "should be common to all people." He even argued that the Old Testament prophets recognized this "mystical and more excellent signification contained" in "the precept of circumcision," since they in fact "command the circumcision of the heart, which all the commandments of Jesus aim at."⁶⁴ John Donne is particularly eloquent on this symbolic displacement: "The principal dignity of this circumcision was that it … prefigured, it directed to that circumcision of the heart." For Donne, "Jewish circumcision were an absurd and unreasonable thing if it did not intimate and figure the circumcision of the heart."⁶⁵

The unexplained displacement of Shylock's cut from Antonio's "flesh" upward to his heart is now considerably clearer. Viewed in light of this familiar exegetical tradition, Shylock's decision to exact his pound of flesh from near Antonio's heart can be seen as the height of the literalism that informs all his actions in the play, a literalism that when imitated by Portia leads to his demise. Also echoing through the trial scene of The Merchant are the words of Galatians 6.13: "For they themselves which are circumcised keep not the Law, but desire to have you circumcised, that they might rejoice in your flesh," that is to say (as the gloss to this line in the Geneva Bible puts it), "that they have made you Jews." Shylock will cut his Christian adversary in that part of the body where the Christians believe themselves to be truly circumcised: the heart. Shylock's threat gives a wonderfully ironic twist to the commentary on Paul's Romans that "he is the Jew indeed … who cuts off all superfluities and pollutions which are spiritually though not literally meant by the law of circumcision."⁶⁶ Psychoanalytically inclined readers will immediately recognize how closely the terms of this Pauline displacement correspond to the unconscious substitution central to Freud's secular theories. Theodore Reik, a disciple of Freud's, interpreted Shylock's bond in just these terms, arguing first that the "condition that he can cut a pound of flesh 'in what part of your body pleaseth me'" is "a substitute expression of castration." Reik adds that when it is later decided that "the cut should be made from the breast, analytic interpretation will easily understand the mechanism of distortion that operates here and displaces the performance from a part of the body below to above."⁶⁷

In repudiating circumcision, [Paul] sought to redirect the Covenant, sever the genealogical bond of Judaism, distinguish Jew from Christian, true Jew from false Jew, and the spirit from the flesh (while retaining in a metaphorical sense the sexuality attendant on the flesh). Yet his actual remarks about circumcision are enigmatic and confusing. It is only mild consolation that they proved no less puzzling to the sixteenth-century theologians who tried to untangle the various levels of Paul's literal and symbolic displacements. Take, for example, the Geneva Bible's gloss to Romans, which reaches new depths of convolution in its attempt to iron out these difficulties by asserting that "Paul useth oftentimes to set the letter against the spirit. But in this place the circumcision which is according to the letter is the cutting off of the foreskin. But the circumcision of the spirit is the circumcision of the heart. That is to say, the spiritual end of the ceremony is true holiness and righteousness, whereby the people of God is known from profane and heathenish men." In their frustration, Paul's interpreters often turned against one another. Andrew Willet, for example, chastised Origen for misreading Paul and "thus distinguishing the circumcision of the flesh; that because there is some part of the flesh cut off and lost, some part remaineth still. The lost and cut off part (saith he) hath a resemblance of that flesh, whereof it is said, all flesh is grass. The other part which remaineth is a figure of that flesh, whereof the Scripture speaketh, all flesh shall see the salutation of God." Willet is sensitive to Origen's conflation of the two kinds of circumcision here, spiritual and fleshly—"Origen confoundeth the circumcision of the flesh and the spirit, making them all one"—but it is hard to see how to maintain hard and fast divisions when, on the one hand, commentators drive a wedge between the spiritual and the physical, while, on the other, they show how even in the Old Testament circumision was used both literally and metaphorically. For Willet, then, the correct interpretation, and one that seems to require a bit of mental gymnastics, requires that we think not of the circumcision of the flesh and the circumcision of the heart "as though there were two kinds of circumcisions" but as "two parts of one and the same circumcision which are sometimes joined together, both the inward and the outward."⁶⁸